Restless Legs Syndrome

An irresistible urge to move the legs — with crawling, pulling, or buzzing sensations — that appears at rest, worsens in the evening, and is relieved by movement. RLS disrupts sleep profoundly, and its most important treatable driver is iron deficiency, even at ferritin levels standard labs call normal.

Evidence synthesis: Brain iron deficiency is the best-established mechanism — dopamine dysfunction downstream of low brain iron — which is why ferritin-guided iron repletion is first-line in guidelines (AASM/IRLSSG): oral iron when ferritin is below ~75 µg/L, with trial evidence showing symptom reduction even without anaemia. Intravenous ferric carboxymaltose has positive RCT evidence for moderate-severe RLS. Dopamine agonists (pramipexole, ropinirole) work but carry a major augmentation risk — symptoms worsen and spread earlier over time — leading guidelines to shift toward alpha-2-delta ligands (gabapentin, pregabalin), which have strong RCT support. Documented aggravators with evidence: caffeine, alcohol, nicotine, sedating antihistamines (diphenhydramine is a classic trigger), and many antidepressants. Sleep deprivation itself worsens RLS, creating a vicious cycle worth breaking.